Thank you both very much. I am almost there now - I have 27 out of 28 children sorted and am waiting on two death certificated for unnamed male children to find out who the missing child is.
Erik Bloodaxe - I'm fascinated to hear that you went to school with Frederick's great grandson. he would be my third 'half' cousin.
Glancare - thanks for the heads up regarding searching through the PRs for Somerset. I had found them but assumed that they were indexed! I should know better by now.
Yes played rugby with him and two of his brothers as well.
Looked through Leighland and Old Cleeve and cant find what I presume are twins.